Friction is a significant problem in all mechanical systems and can result in wear, noise, the generation of excess heat and excessive energy consumption. The reduction of friction is an ever growing concern in the transportation based industries because of the presently escalating costs of fuel and the rising consumer demand for reliable, long lasting vehicles. Engines and drive trains include a large number of moving parts and even a small reduction in friction will have a great economic impact upon land, air and sea based transportation. Similarly, friction is a major problem in all industries which manufacture or utilize systems and equipment having moving parts.
Petroleum based lubricants, either in a liquid or solid form, such as oils, greases and the solid form PTFE of are very important in reducing friction in a variety of mechanical systems; however, petroleum based lubricants, relative to TMDs, have low load carrying abilities which limits their effectiveness and their usefulness in high load bearing applications. In some instances systems include precision parts or working environments that would be contaminated by breakdown and outgassing of liquid lubricants.
Dry lubricants have been developed in response to the various shortcomings of liquid lubricants. Dry lubricants generally comprise materials which are fairly inert and which have a lamellar structure which causes them to be lubricous. Among some of the widely utilized dry lubricants are graphite, talc, molybdenum disulfide, tungsten disulfide, niobium disulfide, and boron nitride. Other dry lubricant materials such as ditellurides and diselenides of various group V and VI metals are also employed. In some instances, particles of a lubricous polymer, such as PTFE or other such fluorocarbon polymers, are utilized as dry lubricants. Dry lubricant materials are generally employed in a loose powdered form, or they may be used in combination with a liquid lubricant. Loosely applied lubricant coatings wear away and must be continually renewed. Further, loose particles of lubricant can contaminate a variety of systems.
In response to these shortcomings, various efforts have been made to develop permanent dry lubricant coatings. The term "permanent" as used to describe the lubricant is meant to define a lubricant film which is tightly bonded and integral with the workpiece surface, and is in contrast to lubricant films which are merely disposed upon the surface. In some instances, articles are coated with fluorocarbon polymers so as to provide a highly lubricous surface; however, these coatings are generally soft and have a tendency to migrate off a substrate surface when exposed to pressures.
Various processes have been developed for bonding dry lubricant coatings to the surfaces of various articles. U.S. Pat. Nos. 3,632,368 and 3,644,133 (the disclosures of which are incorporated herein by reference) describe a method for permanently bonding a coating of tungsten disulfide to metallic workpieces. The process disclosed therein uses a modified sandblasting technique wherein atomically clean surfaces are impacted at a fairly high rate of speed with particles of dry lubricant material. This application discloses an impingement bonding technique.
Permanent lubricant materials can confer a significant advantage in terms of improved operating efficiencies and increased lifetime to engines, transmissions and other components of automobiles, airplanes and other motor vehicles.
The present invention is directed toward producing a lubricious wear and corrosion resistant compound adapted to refrain from migrating away from highly loaded contact areas. Use of the present invention enables the production of vehicles as well as processing equipment, tools, and manufacturing equipment which are longer lasting, more energy efficient and more reliable. These and other advantages of the present invention will be readily apparent from the illustrations, discussion and description which follow.